Fixed ability to merge a list of dicts

cookie_composer/data_merge.py

@@ -5,6 +5,8 @@
 from collections import ChainMap, OrderedDict
 from functools import reduce
 
+from frozendict import frozendict
+
 
 def deep_merge(*dicts) -> dict:
     """
@@ -43,7 +45,7 @@ def merge_iterables(iter1: Iterable, iter2: Iterable) -> set:
     """
     from itertools import chain
 
-    return set(chain(iter1, iter2))
+    return set(chain(freeze_data(iter1), freeze_data(iter2)))
 
 
 def comprehensive_merge(*args) -> Any:
@@ -62,7 +64,7 @@ def comprehensive_merge(*args) -> Any:
     Returns:
         The merged data
     """
-    dict_types = (dict, OrderedDict)
+    dict_types = (dict, OrderedDict, frozendict)
     iterable_types = (list, set, tuple)
 
     def merge_into(d1, d2):
@@ -96,7 +98,7 @@ def merge_into(d1, d2):
 
 
 class Context(ChainMap):
-    """Provides merging and convenence functions for managing contexts."""
+    """Provides merging and convenience functions for managing contexts."""
 
     @property
     def is_empty(self) -> bool:
@@ -106,3 +108,18 @@ def is_empty(self) -> bool:
     def flatten(self) -> dict:
         """Comprehensively merge all the maps into a single mapping."""
         return reduce(comprehensive_merge, self.maps, {})
+
+
+def freeze_data(obj):
+    """Check type and recursively return a new read-only object."""
+    if isinstance(obj, (str, int, float, bytes, type(None), bool)):
+        return obj
+    elif isinstance(obj, tuple) and type(obj) != tuple:  # assumed namedtuple
+        return type(obj)(*(freeze_data(i) for i in obj))
+    elif isinstance(obj, (tuple, list)):
+        return tuple(freeze_data(i) for i in obj)
+    elif isinstance(obj, (dict, OrderedDict, frozendict)):
+        return frozendict({k: freeze_data(v) for k, v in obj.items()})
+    elif isinstance(obj, (set, frozenset)):
+        return frozenset(freeze_data(i) for i in obj)
+    raise ValueError(obj)

requirements/dev.txt

@@ -107,6 +107,8 @@ filelock==3.8.0
     #   virtualenv
 flake8==5.0.4
     # via -r test.txt
+frozendict==2.3.4
+    # via -r test.txt
 frozenlist==1.3.1
     # via
     #   -r test.txt

requirements/prod.in

@@ -2,6 +2,7 @@ aiohttp
 backports.shutil-copytree
 click-log
 cookiecutter>=2.0.0
+frozendict
 fsspec
 gitpython
 pydantic

requirements/prod.txt

@@ -37,6 +37,8 @@ commonmark==0.9.1
     # via rich
 cookiecutter==2.1.1
     # via -r prod.in
+frozendict==2.3.4
+    # via -r prod.in
 frozenlist==1.3.1
     # via
     #   aiohttp

requirements/test.txt

@@ -71,6 +71,8 @@ filelock==3.8.0
     # via virtualenv
 flake8==5.0.4
     # via -r test.in
+frozendict==2.3.4
+    # via -r prod.txt
 frozenlist==1.3.1
     # via
     #   -r prod.txt

tests/test_merge_files_helpers.py

@@ -4,6 +4,7 @@
 from collections import OrderedDict
 
 import pytest
+from frozendict import frozendict
 from pytest import param
 
 from cookie_composer import data_merge
@@ -76,6 +77,19 @@ def test_comprehensive_merge(args: list, expected: Any):
     assert data_merge.comprehensive_merge(*args) == expected
 
 
+def test_comprehensive_merge_list_of_dicts():
+    """A list of dicts should resolve into a list of frozendicts in random order."""
+    result = data_merge.comprehensive_merge([{"a": 1}, {"b": 2}], [{"c": 3}, {"d": 4}])
+    expected = [
+        frozendict({"d": 4}),
+        frozendict({"c": 3}),
+        frozendict({"b": 2}),
+        frozendict({"a": 1}),
+    ]
+    assert isinstance(result, list)
+    assert set(result) == set(expected)
+
+
 def test_context_flatten():
     """Should return a merged dict."""
     context = data_merge.Context(